Bof vessel without bottom brackets



' July 8, 1969 M. c. FALK BOF VESSEL WITHOUT BOTTOM BRACKETS Filed Au 7, 1967 LE JJi/g. 6

3,454,269 BOF VESSEL WITHOUT BOTTOM BRACKETS Martin C. Falk, Pittsburgh, Pa., assignor to Pennsylvania Engineering Corporation, New Castle, Pa., a corporation of Pennsylvania Filed Aug. 7, 1967, Ser. No. 658,702 Int. Cl. C21c 5/50 US. Cl. 26636 12 Claims ABSTRACT OF THE DISCLOSURE A BOF or converter type of ferrous metal refining vessel is equipped with a trunnion ring positioned in a spaced-apart, encircling relation about its metal shell wall. The vessel, as customary, has a refractory lining and an open mouth portion throng-h which a metal charge is introduced, through which an oxygen blow is accomplished, and from which slag and molten metal may be poured when the vessel is tilted after the completion of a metal melting and refining operation. The vessel is supported entirely on the upper side of the ring by a group of opposed mounting assemblies that have brackets that are welded to its shell wall in a peripherally spaced relation on a common bonding area or plane of minimum vertical extent. Each mounting assembly has a centrallypositioned, secondary, angle-shaped, vessel bracket that is diametrically-opposite the same bracket of the other assembly to define a common transverse axis in a direct right angular relation with a common axis defined by the trunnion shafts. Each secondary vessel bracket has its vertical flange weld-secured to the shell wall of the vessel; its horizontal flange extends radially or horizontally into sliding engagement with an inner portion of the upper side of the trunnion ring. Also, each mounting assembly has a pair of bracket assemblies in a peripherally spaced adjacent relation with and between which the secondary bracket is positioned. Each bracket assembly has a primary vessel bracket whose vertical flange is weld-secured to the shell wall and Whose horizontal flange is of thickened section and extends in .a radially-slidable relation along the upper side of the trunnion ring. A pair of opposed spaced-apart guide arms are secured to the upper side of the ring, each by a vertical spacer member structure, for guidably-slidably positioning the upper face of the horizontal flange of each primary bracket. Each spacer structure has an upright guide member that cooperates with the corresponding guide member of the spacer member structure for the other guide arm of the pair to provide a peripheral clearance spacing with opposite vertical sides of the associated horizontal flange of the primary bracket and permit en-dwise or transverse movement of such flange therebetween and across and with respect to the upper side of the ring.

The group of mounting assemblies constitutes the sole means of support and connection of the vessel on and with respect to the trunnion ring. The primary and secondary brackets are shown positioned at substantially right angles to the horizontal axis of a pair of trunnion shafts that are carried by the trunnion ring to provide for transverse sliding movement with respect to the trunnion ring during expansion and contraction of the vessel under temperature and load variations and, at the same time, to permit the vessel to expand and contract along its longitudinal or vertical major axis within the trunnion ring. The substantially single plane, as distinguished from the conventional spaced-apart multiple dual or multiple plane type of support mounting for a vessel, minimizes stress and strain in the vessel shell under longitudinal expansion and contraction, facilitates mounting the supporting trunnion ring at substantially the center of gravity of the vessel with its normal content of molten metal, and thus, minimizes United States Patent 3,454,269 Patented July 8, 1969 "ice turning or tilting power requirements, and provides flexibility in the design of the shape of the furnace vessel in the sense of permitting departure from a conventional shape. The trunnion ring carries a pair of opposed trunnion shafts; each shaft at its inner end is inset within the ring in a non-rotatable relation with respect thereto and is tightly-secured in position along its length within the bore of the ring.

This invention relates to an improved approach to the mounting and support of a furnace vessel on and with respect to its trunnion ring and particularly, to improved mounting means which facilitates relative expansion and contraction between a vessel and its trunnion ring and, which, at the same time, firmly and securely supports the vessel, better accommodates variations in the vessel shape, and minimizes power required for turning a vessel during its utilization.

BOF or converter furnace vessels used in melting and refining metal, such as ferrous metal, have customarily utilized a trunnion ring having opposed trunnion shafts or pins for rotatably supporting the vessel and enabling it to be tilted on a pair of stationary bearing stands during its use. It has been also customary to provide a drive means operatively-connected to at least one of the trunnion shafts for effecting tilting operations. Furnace vessels of this type have increased greatly in capacity from the early Bessemer vessel of 20 to 30 tons, up to present day vessels of 300 to 350 or more tons capacity. It is recognized that vessels of this type and particularly, those utilizing an oxygen blow are subjected to extremes of temperature and to heavy as well as shock loads. For example, a molten metal charge tends to shift with the vessel :during a tilting operation and to ovalize its shape when the metal is to be poured.

Heretofore, it has been customary to provide connecting means between the vessel and its trunnion ring that, in its mounting, requires a considerable secured longitudinal or vertical central banding surface area of the vessel shell, as represented by upper and lower brackets in vertically or longitudinally-spaced, opposed, upper and lower groups for cooperating with upper and lower sides or faces of the trunnion ring. A mounting of this type which involves spaced-apart planes of connection and support inherently fixes a central area of the vessel with respect to the trunnion ring, such as to inhibit free longitudinal vertical expansion of the vessel with respect to the ring and thus, gives rise to stresses and strains that tend to shorten the life of the vessel and particularly, its shell.

Heretofore, those skilled in the art have believed it to be necessary to provide upper and lower bracket support assemblies or connections between a trunnion ring and a furnace vessel. An improved construction recently devised provides lower bracket assemblies in an opposed relation with upper bracket assemblies, with the lower assemblies having a slight clearance or spaced relation with respect to the lower face of the ring. The theory of this construction is that limited longitudinal expansion in the vertical extent of the vessel representing the dis tance between the upper and lower bracket supports will provide for some longitudinal expansion of the vessel shell between the rigid connections of such upper and lower support brackets, and that beyond this permitted limited expansion, the engagement of the bottom edge or side of the ring with the bottom brackets will provide necessary security of connecting support between the ring and the vessel, and particularly will permit the ring to close up such clearance space when, for example, the vessel is tilted or is revolved to an upside down position.

However, it has been determined that such a type of supported relation does not provide for a full longitudinal expansion of the vessel shell and that it is diflicult to select and judge the proper clearance spacing for permitting the limited contemplated type of expansion of the central area of the furnace. In actual ractice, furnace vessels are subjected to unusual stresses and strains and uncontemplated distortions and elongations that cannot be compensated by such a type of mounting arrangement and thus, set up breakage strains which shorten the life of the vessel. In accordance with the present invention, it has been discovered that bottom supports can be eliminated and are not essential, as heretofore thought by those skilled in the art, and that the reduced stresses and strains engendered by an upper, substantially single plane of connection is an important factor which makes a bottom type of support unnecessary. Further it has been determined that the use of rivet mounting for the support brackets in order to give more flexibility to the mounting is no longer necessary, and that a secure weld connection may now be successfully employed. There is a definite advantage in avoiding a central banding area as defined by vertically spaced-apart upper and lower securing means and within which longitudinal expansion is restricted or limited as to the furnace vessel, and in permitting the central area, from a common, central, single plane of support, to fully follow top and bottom end portions of the vessel in its longitudinal expansion and contraction. This has all been made possible by the discoveries of the present invention and the simplified mounting or supporting bracket utilization which has been devised.

It has thus been an object of the present invention to evaluate various conflicting factors involved in the mounting and employment of a vessel in a supported position on a trunnion ring and to reach a practical simplified Solution of the problem involved.

Another object has been to provide an improved type of vessel connection and support with its trunnion ring that will eliminate or at least minimize adverse factors which have arisen in the use of prior conventional types.

Another object has been to devise a secure and effective supporting connection between a vessel and its trunnion ring which Will facilitate the use of vessels of different shapes and which will enable at least closely approaching an alignment of the center of rotation of the vessel with the center of gravity of the vessel as charged.

A further object has been to meet adverse factors present in prior vessel support constructions and to devise a new structure that will substantially eliminate the need for vertically-spaced support areas along the vessel shell.

A still further object of the invention has been to provide a practical mounting assembly means which will enable a vessel to be effectively and fully connected to and supported by a trunnion ring only from one side of the ring and particularly, from the upper or top side thereof.

These and other objects of the invention will appear to those skilled in the art from the described embodiment and the claims.

In the drawings:

FIGURE 1 is a top plan View of a furnace vessel and trunnion ring utilized and constructed in accordance with the invention; in this figure, a portion of one bracket assembly is broken-away in section to better illustrate its construction;

FIGURE 2 is a side view in elevation on the scale and of the apparatus of FIGURE 1; this view is partially broken away to show the wall construction of the furnace;

FIGURE 3 is an enlarged sectional view in elevation, taken along line IIIIII of FIGURE 1; and particularly illustrating the construction and mounting of a bracket assembly of the invention that employs a primary bracket;

FIGURE 4 is a fragmental section in elevation on the scale of FIGURE 3, taken along the line IVIV of FIG- URE 1, and particularly illustrating the construction of the trunnion ring and the mounting of a trunnion shaft projecting therefrom; and

FIGURE 5 is a further enlarged perspective view in elevation, showing details of the construction of main bracket assemblies; in this figure, one trunnion-mounted holding bracket assembly of an opposed pair is omitted.

In carrying out the invention, a converter or furnace vessel 10 having a refractory lining 10a and an outer metal shell 10b is carried and supported on a group of peripherally-spaced, opposed mounting assemblies A and A, shown as having angle-shaped primary and secondary brackets 16 and 15 whose vertical flanges are Welded in an aligned relation to the outer metal shell of the vessel, and whose horizontal flanges project radially-outwardly therefrom to slidably-engage or cooperate with an upper side or face of a trunnion ring 11. As shown particularly in FIGURE 1, each primary bracket 16 is a part of a bracket assembly B, and each bracket assembly B of one mounting assembly A has a diagonally-opposed relation with one assembly B of the other mounting assembly A. In the mounting assemblies A and A', the bracket assemblies B and their primary brackets 16 are essential; however, the secondary brackets 15 may be omitted under appropriate conditions. Each secondary bracket 15 of one mounting assembly A has a diagonally-opposed relation with the bracket 15 of the other assembly A. The mounting assemblies A and A (bracket and bracket assembly groups) lie along a transverse, horizontal or radial plane of the vessel 10 that is substantially perpendicular or at right angles to the corresponding common axis of a pair of opposed trunnion shafts 12 projecting from the trunnion ring 11. By weld-securing the faces of vertical flanges of the brackets on each group to the converter shell, bolt holes are eliminated.

Each mounting assembly A and A is shown provided with a pair of the bracket assemblies B and with one centrally-positioned secondary vessel bracket 15. The secondary vessel bracket 15 is in the form of an angle member having its horizontal flange or foot portion in abutting, sliding engagement with the upper side or face of the trunnion ring 11. As shown in FIGURES 3 and 5, each primary bracket 16 is also of angle-shape and has the upper sides or face of its thickened horizontal flange or foot portion 16a slidably-cooperating with a pair of opposed, spaced-apart, horizontal, peripherally-extending guide arms 17 through the agency of shims 18. The horizontal flange or foot 16a is shown extending radially along and toward the other periphery of the trunnion ring 11, and as slidably-engaging the upper side of the ring on its under face. A holder assembly or vertical spacer structure is positioned between the upper face of the ring 11 and the under side of each guide arm 17; this structure includes an upright guide-spacer member 19 and reinforcing plate or wing members 20 that are all weld-secured between the upper face of the ring 11 and the under face of the associated guide arm 17. The pair of guide members 19 of each bracket assembly B extend radially or transversely on the ring 11 to define peripheral clearance spacing to receive opposite vertical sides of the thickened horizontal flange 16a of the associated primary vessel bracket 16. This provides a pair of upright guides 19 for endwise-sliding movement of the flange 16a therebetween; it will be noted that an associated pair of upright guides 19 and an associated pair of horizontal guide arms 17 define a slide slot for each flange 16a, and that the flange 16a has a thickness substantially corresponding to the spacing between the upper face of the ring 11 and the under faces or sides of guide arms 17.

A group of the reinforcing plate or wing members 20 are shown weld-secured between each upright guidespacer member 19 and the opposed top face of the trunnion ring 11 and under face of the associated guide arm 17 in a peripherally-extending and radially spaced-apart relation with each other for reinforcing the mounting of the holder assembly. As shown particularly in FIGURE 3, each foot portion 16a of each primary furnace bracket 16 is thus firmly-guidably positioned between the pair of opposed, spaced, guide arms 17 and the upper side or face of the trunnion ring 11, in such a manner that endwise, radial-outward-inward, transverse or horizontal sliding movement is provided for or permitted with respect to the trunnion ring 11.

Referring particularly to FIGURES 1 and 4, the trunnion ring 11 is shown provided with a pair of trunnion shafts or pins 12 which extend radially therethrough. Each shaft 12 has a polygonal or rectangular flange or shoulder 12a on its inner end that is inset within a complementary opening in the ring in a substantially flush relation with the inner periphery thereof. The shaft 12 has a secure, tight fit within the ring 11 and, if desired, an opposed outer flange or shoulder 12b may be provided. The shaft is securely-mounted in position against walkout or relative rotation, even under severe rotational stress.

The vessel thus has a mounting which lies along substantially one transverse, horizontal or diametric plane of the vessel 10, and only along the upper side or face of the trunnion ring 11. Since a trunnion ring 11 may have a vertical width or extent of about seven to eight feet, for a vessel having a shell of about twenty-six feet in vertical length, it will be apparent that the present construction wherein there is no bracket mounting between the vessel and the underside of the ring, eliminates a considerable area on the vessel which would normally, using upper and lower mounting brackets, define a somewhat rigid longitudinal or vertical band or segment area on the vessel that tends to inhibit longitudinal or vertical expansion of the vessel during its use or, in other words, tends to set up stresses and strains in a central area about the vessel that limits its life and causes failure of the shell. The present construction, however, is such that longitudinal or vertical expansion of the vessel is free from a substantially single, transverse, central support plane, upwardly or downwardly therefrom, when the vessel is in its normal operating position. The frictional engagement of the primary brackets 16 and the secondary brackets with the trunnion ring 11 and trunnion mounted holding assemblies is such that provision is made for a major amount of radial or diametric expansion 1 of the vessel with respect to the ring.

In addition to the above important advantages, the mounting construction of the invention permits the vessel shell to be held in perfect alignment without slip during turning movement thereof, simplifies shell maintenance removal, gives a high degree of structural and mechanical strength, and substantially eliminates deforming stress and strain on the vessel shell and between it and the trunnion ring. The simplicity and nature of the mounting makes it possible to place the axial center line of tilt, as represented by the trunnion shafts 12 at substantially the center of gravity of the vessel 10 with a normal load of molten metal therein. This minimizes power or torque requirements in turning the vessel and in deskulling it. It also makes practical the use of various vessel shapes other than a rounded conventional shape. If desired, rollers (not shown) may be positioned along the inner periphery of the trunnion ring 11 to further the support of the vessel shell without losing the advantages made possible by the mounting construction.

Although an embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from its spirit and scope.

I claim:

1. In an open-mouth converter type of furnace vessel having an outer metal shell wall and adapted to be rotatably-positioned on a pair of bearing stands for melting and refining metal in its upright position, an improved combination defined when the vessel is in its vertical upright position as follows:

a group of opposed mounting assemblies having a substantially right angular relationship with respect to said axially-aligned trunnion shafts for supporting the vessel on said ring,

said group of opposed mounting assemblies being connected to the shell wall on a common transv rse plane on opposite sides of the vessel entirely adjacent an upper side of said ring,

each opposed mounting assembly of said group having at least one bracket assembly,

each of said bracket assemblies comprising, a primary angle-shaped vessel bracket having a vertical flange positioned along the metal shell wall and weldsecured thereto and having a horizontal flange of thicker section extending horizontally-outwardly towards the outer periphery of and with its under face slidably-engaging the upper side of said trunnion ring, a pair of opposed spaced-apart and peripherallyextending guide arms secured on the upper side of said ring in an upwardly-spaced relation with respect thereto to guidably-slidably position the upper face of said horizontal flange of said primary bracket with respect to said ring, a vertical spacer member structure weld-secured between the upper side of said ring and the underside of each of said guide arms and having an upright guide member cooperating with a corresponding upright guide member of the other guide arm of said pair to define a peripheral spacing and to guidably-slidably position opposite vertical sides of the horizontal flange of said primary bracket for movement of said horizontal flange transversely on and with respect to the upper side of said ring,

and the bracket assembly of said mounting assembly group on one side of the vessel being in a diametrically-opposed position with respect to and on the same transverse plane as the bracket assembly of said group on the opposite side of the vessel.

2. A combination as defined in claim 1 wherein, each of said opposed mounting assemblies has a pair of peripherally spaced-apart bracket assemblies of the same defined construction and mounting, and the other bracket assembly of one mounting assembly has a diametricallyopposed relation with the other bracket assembly of the other mounting assembly.

3. A combination as defined in claim 1 wherein, each of said opposed mounting assemblies having a secondary angle-shaped vessel bracket provided with a vertical flange extending along the metal shell wall and weldsecured thereto in a peripherally spaced adjacency with respect to said primary bracket and provided with a horizontal flange extending transversely-outwardly in an abutting slidable relation with the upper side of said ring, and the vertical extent of the vertical flange of said secondary vessel bracket being aligned with and within the maximum vertical extent of the vertical flange of said primary vessel bracket of the same mounting assembly, and the secondary bracket of said group on one side of the vessel being in a diametrically-opposed position with respect to and on the same transverse plane as the secondary bracket of said group on the opposite side of the vessel.

4. A combination as defined in claim 3 wherein, each of said opposed mounting assemblies has a pair of bracket assemblies of the same defined construction, and the secondary bracket of each of said opposed mounting assemblies is positioned between the pair of bracket assemblies of the same mounting assembly.

5. A combination as defined in claim 4 wherein, said secondary brackets are positioned on a diametric axis that is at right angles with the axis of said trunnion shafts, and diametric axes of opposed bracket assemblies of said mounting assemblies are positioned on adjacent axes along opposite sides of said secondary brackets.

6. A combination as defined in claim 5 wherein the horizontal flange of each of said primary brackets is of greater thickness than the horizontal flange of each of said secondary brackets.

7. A combination as defined in claim 1 wherein, each of said vertical spacer member structures has a group of wing members weld-secured peripherally to and behind an associated upright guide member and between the upper side of said ring and the underside of an associated guide arm, and the thicker section of the horizontal flange of said primary bracket corresponds substantially to the vertically spacing between said pair of opposed guide arms and the upper side of said trunnion ring.

8. A combination as defined in claim 7 wherein shims are positioned between the underside of said pair of opposed guide arms and the upper side of the horizontal flange of said primary bracket.

9. A combination as defined in claim 5 wherein the vertical weld-secured extent of the vertical flange of each of said secondary vessel brackets corresponds to the vertical weld secured extent of the vertical flange of each of said primary vessel brackets.

10. A combination as defined in claim 1 wherein each of said trunnion shafts extends transversely through said ring and has an inner flange inset in a locking relation Within said ring along its inner periphery, and has a tightly-secured positioning along its length within said ring.

11. A combination as defined in claim 10 wherein said inne rfiange is of polygonal shape and fits within a polygonally-spaced recess in said trunnion ring.

12. A combination as defined in claim 11 wherein each of said trunnion shafts has an outer opposed flange in abutment with the outer periphery of said ring.

References Cited UNITED STATES PATENTS 9/1961 Puxkandl. 5/1965 Krause 266-35 X 

